The suit, which the states are to announce on Tuesday, contends that the administration did not do a rigorous enough analysis of the environmental benefits of fuel economy regulations, as required by law, before issuing new rules last month for S.U.V.'s, pickup trucks and minivans. The suit will also claim that the government did not consider the impact of gasoline consumption on climate change when devising the new rules.
While the states have initiated a number of suits over Washington's environmental policies, the new suit is the first to take aim at federal fuel economy regulations. With gasoline reaching $3 a gallon in many parts of the country, there has been a broad outcry for action but little consensus on what to do.
Senate Republicans have proposed a $100 rebate to help taxpayers pay gas bills, a proposal that has been met with criticism even from the right, while President Bush has asked for Congressional authority to revise mileage regulations for passenger cars. He already has the authority to do so for S.U.V.'s and other trucks.
California will be lead plaintiff in the suit, which also includes Connecticut, Maine, Massachusetts, New Jersey, New Mexico, Oregon, Rhode Island and Vermont, as well as New York City and the District of Columbia. Many of the same states have teamed up in other environmental suits against the administration, though with mixed success; a recent suit against the Environmental Protection Agency over power plant emissions was dismissed.
"It's disappointing when you see power exercised to benefit the auto industry rather than consumers or environmental challenges," said Bill Lockyer, the attorney general of California, discussing the Bush administration's fuel economy rules.
The attorney general of Massachusetts, Thomas F. Reilly, said in a statement, "At a time when we are all facing a gas crisis, the Bush administration is pushing for fuel economy standards that appear to be authored by the oil and auto industries."
Rae Tyson, a spokesman for the National Highway Traffic Safety Administration, said he could not comment on the suit because he had not seen it. But Mr. Tyson defended the regulations and said, "There's no question the analysis was rigorous."
Several top Democrats, and also some Republicans, including Senator John McCain of Arizona, have called for tougher mileage requirements for S.U.V.'s, which must meet less stringent fuel economy guidelines because they are classified in the same category as light trucks, instead of with passenger cars .
Late last year, the Bush administration unveiled the first broad overhaul of mileage regulations for S.U.V.'s, pickup trucks and minivans since the rules were created in the 1970's. Currently, each automaker's annual production of passenger cars must average 27.5 miles a gallon, while light trucks, which include S.U.V.'s, must average 21.6 miles a gallon in 2006 models.
The administration's new system would take the single truck category and break it up into a number of smaller categories with varying requirements. Government officials predict that overall truck fuel economy will rise to 24 miles a gallon by 2011, though it will depend on the sales mix among S.U.V.'s and other trucks.
Automakers have said the new regulations are tough enough.
Jennifer Moore, a spokeswoman for the Ford Motor Company, referred to a previous company statement that commended the traffic safety agency for creating a new regulatory system that would "pose significant challenges" but also be "more equitable to every automaker."
An overdependence on sales of large S.U.V.'s like Hummers, Chevrolet Suburbans and Ford Explorers is seen as among the reasons General Motors and Ford, the last two American-owned automakers, are suffering steep losses and closing plants.
Environmentalists say the Bush administration's new truck fuel economy system will not do enough to curb oil consumption and adds uncertainty to a complex system already characterized by loopholes.
In setting the standards, the administration "looked high gas prices, oil addiction and global warming squarely in the eye and blinked," said Daniel Becker, the director of the global warming program at the Sierra Club.
The administration is, however, closing one loophole, an exemption that has left the largest S.U.V.'s, including the Hummer H2, outside the regulatory system.
But the administration's rules are considerably less daunting than new California global warming emissions regulations that would force steeper fuel economy increases on vehicles sold there. New York is planning to pass similar air-quality rules. The industry is challenging the state rules in court, and the administration has strongly opposed the movement by states to regulate global warming emissions.
Mr. Tyson, of the traffic safety agency, said many other factors were considered in addition to the price of gas, including "the ability of industry to be able to meet the standard."
"You can't propose something that's not technically feasible for them to achieve," he added.